360 LAND AND FRESH-WATER SHELLS OF N. A. [PART IV. 



A very neat species which Mr. Reeve seems to have over- 

 looked. The localit}'- given in the above description is prob- 

 ably incorrect. Mr. Lea has recently stated his opinion that 

 this and other species, to which he originally assigned Tusca- 

 loosa as tlie habitat, were not reall}' found there. Indeed the 

 present state of our knowledge of the species of this genus 

 leads us to believe that they are entirely confined to the waters 

 of the Coosa River. It is wonderful that this group occupies 

 such a restricted space, wliile othei'S, such as Lithasia, Pleuro- 

 cera, etc., extend over nearly the whole of the country between 

 the Mississippi River and the Alleghany Mountains. 



8. S. amplum, Anthony. 



Gyrotoma ampla, Anthony, Proc. Acad. Nat. Sci., p. 6G, Feb., 1860. Binnet, 



Check List. No. .30!;. Brot, Li--t, p. -27. 

 Melatoma amplum, Anthony, Reeve, Monog., t. 3, sp. 16. 



Description. — Shell smooth, ovate, rather thick, olivaceous ; spire 

 not elevated, but acute ; whorls G-7, subconvex ; sutures well defined ; 

 fissure broad, rather deep and waved; aperture moderate, elliptical, 

 flesh-colored and banded within ; columella smooth, or slightly thick- 

 Fig. 681. Fig. 682. encd only at the fissure ; body-whorl striate and 

 banded ; whorls of the spire not banded, but 

 having a thickened, cord-like line near the sut- 

 ure. 



Habitat. — Coosa Kiver, Alabama. 

 Length, eleven-sixteenths; breadth, seven- 

 sixteenths of an inch. Length of aperture, seven-sixteenths ; breadth 

 of aperture, four-sixteenths of an inch. 



Observations. — A fine, symmetrical species of this interesting genus, 

 which hitherto has not been very productive in species. Compared 

 with S'diinostoma funicniatum, Lea, which it most nearly resembles, 

 it is smoother, thinner, more acute and has not the double cord-like 

 lines of that species. Most, if not all the species of Gyrotoma, have 

 the fissure gradually filled up behind as it is pushed forward in the 

 process of growth, by a cord-like line more or less prominent, often 

 so much so as to produce quite a shoulder at the suture, and this 

 species is so marked, but it has no cord-like line in the middle of the 

 body-whorl, as described m faniculatum. — Anthony. 



A beautiful species, which may be readily distinguished from 



